1. Technical Field of the Invention
This invention relates generally to wireless communication systems, and more particularly to communication monitoring and relay operations by wireless communication devices within such wireless communication systems.
2. Related Art
Wireless communication systems are known to support wireless communications between wireless communications devices affiliated with the system. Such wireless communication systems range from national and/or international cellular telephone systems to point-to-point in-home wireless networks. Each type of wireless communication system is constructed, and hence operates, in accordance with one or more standards. Such wireless communication standards include, but are not limited to IEEE 802.11, Bluetooth, advanced mobile phone services (AMPS), digital AMPS, global system for mobile communications (GSM), code division multiple access (CDMA), wireless application protocols (WAP), local multi-point distribution services (LMDS), multi-channel multi-point distribution systems (MMDS), and/or variations thereof.
An IEEE 802.11 compliant wireless communication system includes a plurality of client devices (e.g., laptops, personal computers, personal digital assistants, etc., coupled to a station) that communicate over a wireless link with one or more access points. The transmitting device (e.g., a client device or access point) transmits at a fixed power level regardless of the distance between the transmitting device and a targeted device (e.g., station or access point). Typically, the closer the transmitting device is to the targeted device, the less error there will be in the reception of the transmitted signal. However, as is generally understood in the art, wireless transmissions may include some error and still provide an accurate transmission. Thus, transmitting at power levels that provide too few errors is energy inefficient. But, transmitting at too high a power may interfere with other access points and/or client devices in the proximate area.
As is also generally understood in the art, many wireless communications systems employ a carrier-sense multiple access (CSMA) protocol that allows multiple communication devices to share the same radio spectrum. Before a wireless communication device transmits, it “listens” to the wireless link to determine if the spectrum is in use by another station to avoid a potential data collision. At lower received power levels, this protocol can lead to a hidden terminal problem when two devices, generally spaced far apart, are both trying to communication with a third device in the middle. While the device in the middle can “hear” the two devices on the periphery, these two devices cannot hear one another—potentially creating data collisions with simultaneous transmissions destined for the middle device.
Additional operational difficulties relate to client devices that operate on the fringe of the coverage area of the access point. During some operations, the access point and client device may adequately communicate but during other operations the same access point client device may not adequately communicate, resulting in loss of service, multiple retransmissions, and other degradation of service quality for not only the inaccessible client device but for other client devices as well.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of ordinary skill in the art through comparison of such systems with the present invention.